Facebook

Facebook is one of the most popular social networking sites on the Web, with millions of registered and active users.

Created in 2004 by Harvard student Mark Zuckerberg (and launched as thefacebook.com), the site was initially only open to users with a collegiate email address. By 2006, the site was open to anyone 13 years or older with an email address.

At the core of Facebook has always been maintaining a profile page, which includes an image of the user, their location, birthdates, interests and forms of contact information, and being “friends” with people on the site. Status updates, high scores in social games and new photos all appear in the constantly updating News Feed, which is the first thing users see after they log in.

Facebook has had its share of troubles. Concerns over privacy management, rolling out new features without alerting the users and lawsuits from people involved with the creation of Facebook (notably Eduardo Saverin) have all at one time or another hounded the site.

Facebook’s creation, as well as those involved, was dramatized in the 2010 film “The Social Network.”